The invention relates to a device for sintering sinter products, comprising a tray accepting the sinter products that is arranged on a base plate, an interior chamber accommodating the sinter products as first interior chamber, a pot-shaped cover, which surrounds the tray and possesses a rim that is sealed towards the base plate, with a protective-gas supply and discharge opening connecting to an interior chamber encompassed by the pot-shaped cover as the second interior chamber, as well as a sintering chamber, which surrounds the pot-shaped cover and the base plate, as the third interior chamber.
The invention further relates to a method for sintering sinter products, such as materials prone to oxidation, in particular metallic sinter products, in particular in form of a dental framework, using a device that comprises a tray arranged on a base plate, with an interior space that accepts the sinter products as the first interior chamber, a pot-shaped cover, which encompasses the tray and has a rim that is sealed towards the base plate, as well as openings for discharge and supply of protective gas connecting to the interior chamber that is surrounded by the cover as the second interior chamber, whereby protective gas flows through the second interior chamber surrounded by the pot-shaped cover.
A device and method of the above-mentioned type are described in DE 20 2010 007 606 U1 and DE 20 2010 002 533 U1. For this purpose, dental frameworks consisting of a silver palladium alloy or chromium cobalt alloy are sintered in a tray, which consists of quartz and is supported at elevation on a fireclay block in a sintering furnace. The fireclay block and the tray are surrounded by a quartz vessel that is sealed by a graphite gasket towards a base plate, on which is arranged the fireclay block. Both the base plate and the fireclay block have bore-hole openings, in order to be able to flush the interior chamber, which contains the quartz tray and is surrounded by the quartz vessel, with a protective gas such as argon. In order to prevent oxidation of the frameworks, the sintering is performed in a protective gas atmosphere. Since an undesirable corrosion of the quartz takes place at temperatures around 1200° C., one coats this in advance with a boron nitride spray. The material to be sintered is placed in the tray of inert pellets of corundum, alumina, or zirconia.
This device suffers from the disadvantage that it can not be used at temperatures above 1200° C.; since on the one hand the life expectancy of quartz is highly limited at these temperatures and on the other, direct contact with finger grease as a result of handling the quartz materials leads to spalling.
DE 20 2011 106 734 U1 relates to a device for the oxygen-free sintering of metal or ceramics and comprises a base plate, upon which is supported a dome. Within the dome, a sintering crucible, into which sinter products may be placed, is supported via a support plate. Also present are openings for the supply and discharge of protective gas. As suitable materials for the device are listed quartz glass or re-crystallized silicon carbide.
WO 94/16642 A1 relates to a furnace, in which is arranged a furnace chamber, which on the fore-side is covered by a lid, through which gas is allowed to flow when protective gas is introduced into the furnace chamber.
Subject matter of EP 2 101 133 A1 is a sintering furnace for dental preparations.
DE 10 2008 012 578 A1 relates to a dental furnace, which is used to perform various heating cycles. An overshoot of the heating output may occur during this.
DE 20 2011 005 465 U1 relates to a device for the oxygen-free sintering of metal or ceramics. In this, the product to be sintered in a sintering container is embedded in sintering granules, which for example may consist of zircon granules.